A fired up and angry Donkey Kong champ has let loose on the witness box, describing why he is suing a Brisbane YouTuber over a “heinous” video he alleges gave rise to an imputation he hounded a young man to his death.

Donkey Kong and Pac-Man arcade champion Billy Mitchell claims a Queensland YouTuber defamed him through a video about a critics death, a judge has heard.

An American arcade gamer known for high scores in Donkey Kong claims a Queensland YouTuber damaged his reputation by linking him to a critic's suicide, a judge has heard. William 'Billy' Mitchell, 59, faced Brisbane District Court on Monday for his defamation trial against Cairns-based video creator Karl Jobst, aged 38.

Concerns about a famous American arcade gamer using his phone inside a courtroom during a defamation trial have been raised by a judge.